Erasing

Erasing the drum surface before creating a new image

After completion of transfer and cleaning, the just printed latent image still has to be erased in order to allow for the recording of a new image..

This is classically obtained by using an AC magnetic head that extends over the full width of the drum. The alternative current fed to the erasing head spatially creates a leakage magnetic field which amplitude decreases with distance. Due to the rotation of the drum, the magnetic dots in the image are therefore exposed to this alternative field of decreasing amplitude. As a result, their magnetic state cycle on minor hysteresis loops that ultimately end up close to zero-magnetization.